Portable fluid fuel air heater

ABSTRACT

A portable fluid fuel air heater comprising a combustion chamber adapted to accommodate a combustion of a fluid fuel; a supply conduit for supplying said fluid fuel to the combustion chamber; at least one electrical device required for the operation of the heater mounted on board the heater; an outer surface of the heater comprising a cavity-like portion for receiving an electric battery in a removable manner up to an operative position of the battery in which the battery is adapted to electrically power the electrical device and is at least partially inserted into said cavity-like portion, said cavity-like portion being configured to keep the battery outside the outer surface of the heater in said operative position of the battery.

FIELD OF THE INVENTION

The present invention relates to a fuel air heater, e.g. a fluid fuelheater, of the portable type, i.e. configured to be easily moved andtransported by a person in order to place it in an operative location,and more specifically to a portable fuel air heater having an electricbattery on board from which it arises an amount of electrical energy forpowering electrical devices required for the operation of the heater,for example an electric fan for generating a forced combustion air flowin the combustion chamber.

BACKGROUND

Portable heaters for heating the air of an environment are known, whichportable heaters use the combustion of a fuel, e.g. a fluid fuel.

In order to perform the combustion, they generally use a forcedcombustion air flow which, together with the fuel, causes the combustionin the combustion chamber.

The forced combustion air flow is sometimes generated by an electric fanmounted on board the heater and upstream of the combustion chamber, andsuch a fan is to be activated for the whole duration of the combustion.

The need to make the operation of the heater independent from theelectrical energy distribution network has led to some attempts to usean electric battery or thermoelectric cells mounted on board the heater.

Since the electric battery mounted on board must electrically power thefan for the whole duration of the operation, it needs to have a veryhigh energy capacity to avoid such a battery from quickly dischargingand the duration of the operation from being excessively short.

However, high capacity electric batteries are often cumbersome andheavy, thereby countering the need to make the heater as lightweight andcompact as possible.

Some attempts to solve this problem have been made by mounting arechargeable electric battery and a battery recharging device inside theheater.

Thereby, a battery with smaller dimensions may be used, but the heaterneeds to be repeatedly connected to the power distribution network eachtime the battery mounted on board is discharged and needs to berecharged. If no distribution network electric socket is available closeto an operative position of the heater, the operation thereof needs tobe interrupted each time, the heater needs to be transported to anelectric socket and connected to such an socket for the time required tobe charged.

In the meantime, there would be no other alternative for heating theoperative position other than using another charged heater, with thesubsequent need to arrange a plurality of heaters to be alternated withone another and to transport them between a recharging station and anoperative position.

Therefore, these known heaters have the disadvantage of not allowing acontinuous, prolonged operation, other than for the duration of thebattery operation time of the rechargeable battery mounted on board,which battery powers the electrical devices required for the operationof the heater which are mounted on board, for example a fan forsupplying combustion air to the combustion chamber.

U.S. Pat. No. 8,068,724 provides a support fastened to an upper surfaceof a tank, having an adjustable panel which can be fastened to thesupport to allow access to an inner chamber defined by the support. Theinner chamber is adapted to contain components of the heater therein,such as an energy source, a control and ignition circuitry, cables,tubes, etc.

This device has various disadvantages, including the fact that in orderto replace an internal component, e.g. the battery, the fastening meansof the adjustable panel must be acted on, the panel removed or moved,the inside of the inner chamber accessed, the battery identified amongthe other components, the battery electrically disconnected, releasedand removed.

All these operations make replacing the battery rather complicated andlaborious, in addition to requiring specific technical skills to avoiddamaging the other components contained inside the inner chamber and toprevent an operator from involuntarily coming into contact with internalcomponents of the heater.

Therefore, the replacement of the battery in such a device does notoccur in order to replace a discharged battery with a charged one, butto replace a battery which no longer works with a new one, i.e. theintervention allowed on such a heater is an occasional technicalmaintenance operation by a specialized technician at a specific servicecenter, not the ordinary and quick replacement of a discharged batterywith a charged battery by a normal user in any location, even a dustyand humid one such as a worksite.

Another disadvantage of this known device is that the impermeability ofthe inner chamber which contains the battery and the electroniccircuitry may only be ensured when the adjustable panel hermeticallycloses the inner chamber of the support. However, such a panel needs tobe removed to access the inside of the inner chamber in order to replacethe battery, therefore such a known device does not allow thereplacement of the battery at a worksite.

Therefore, there is a need to provide a portable fuel air heater havingan electric battery which can be easily and quickly replaced, even by anunskilled person, and even under dusty and unfavorable environmentalconditions, such as e.g. at a worksite.

SUMMARY OF THE INVENTION

It is the object of the present invention to devise and provide aportable fuel air heater which allows the aforesaid needs to be metwhile at least partially obviating the drawbacks indicated above withreference to the known art.

In particular, it is a task of the present invention to provide a fuelair heater which allows a quick and simple replacement of a battery alsoby unskilled users, thus avoiding the need to resort to a servicecenter.

It is therefore the object of the present invention to provide aportable fuel air heater which allows the battery to be easily andquickly replaced while avoiding the need to open a containmentcompartment adapted to contain the battery.

It is also an object of the present invention to provide a portable fuelair heater which allows a quick replacement of the battery whileavoiding an inner compartment comprising other electric or electronicheater components from being accessed.

It is also an object of the present invention to provide a portable fuelair heater which allows the battery to be replaced while avoiding theaccidental contact with other components arranged inside the heater.

It is another object of the present invention to protect the inside ofthe heater from involuntary introduction of dust or liquids or foreignbodies or tools, and also from the contact by a user during thereplacement of the battery.

These and further objects and advantages are achieved by means of aportable fuel air heater in accordance with the appended claims, thedefinitions of which form an integral part of the present description.

Due to the simple and quick replacement of the battery while avoiding aninner chamber from being opened by removing a closure panel, the batterymay be replaced on site, even at a worksite, without the need totransport the heater close to an electric socket for recharging thebattery mounted therein.

It will therefore be sufficient to recharge a plurality of batteriesoutside and independently of the heater, close to a power distributionnetwork, while leaving the heater at the worksite, and to transport thebatteries alone to the heater at the worksite to apply one or more ofthem at a time on the heater until they have a sufficient charge amountfor the operation thereof.

Therefore, when each battery applied on the heater is discharged, it canbe easily and quickly replaced by a charged battery, without removingthe heater from its working position.

Thereby, the heater will be capable of operating for a total durationequal to the sum of the duration of the operation of each chargedbattery.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will becomeapparent from the following description of preferred embodimentsthereof, given only by way of a non-limiting, indicative example, withreference to the accompanying drawings, in which:

FIG. 1 shows a bottom perspective view of a heater according to theinvention, in which the battery is removed;

FIG. 2 shows the perspective view in FIG. 1, in which the battery isdepicted in a battery inlet position;

FIG. 3 shows the perspective view in FIG. 1, in which the battery isdepicted in an operative position of the battery;

FIG. 4 shows an enlarged view of a cavity-like portion for a battery ofthe heater in FIG. 1;

FIG. 5 shows a longitudinal sectional view passing through a main axisof the combustion chamber;

FIG. 6 shows an enlarged detail of FIG. 5, comprising the cavity-likeportion for the battery;

FIG. 7 shows a front view of a heater according to the invention;

FIG. 8 shows a perspective view of an example of removable battery whichmay be used in the heater in FIG. 1;

FIGS. 9 and 10 show a side view and a front view, respectively, of thebattery in FIG. 8;

FIG. 11 shows a cross-section view of a heater according to theinvention according to a sectional plane XII which is orthogonal to themain axis of the combustion chamber, in which the battery is inoperative position and is depicted diagrammatically;

FIG. 12 shows an enlarged detail of FIG. 11;

FIG. 13 shows an enlarged detail of a longitudinal sectional view of theheater in FIG. 5, wherein the battery is in operative position and isdepicted diagrammatically.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS

With reference to the drawings, a portable fluid fuel air heateraccording to the invention is indicated as a whole with numeral 1.

The portable fluid fuel air heater 1 comprises a combustion chamber 2adapted to accommodate a combustion 5 of a fluid fuel 6, a supplyconduit 3 for supplying said fluid fuel 6 to the combustion chamber 2,at least one electrical device required for the operation of heater 1mounted on board the heater.

For example, said at least one electrical device comprises an electricfan 4 adapted to introduce a forced combustion air flow 49 into thecombustion chamber 2 to perform the combustion 5 during the operation ofthe heater.

In accordance with an embodiment, said at least one electrical devicecomprises at least one of the following devices:

-   -   an electric starter 43 adapted to trigger the combustion in the        combustion chamber 2, for example arranged in the combustion        chamber 2;    -   a thermostat 42 adapted to provide a temperature signal, for        example arranged in the combustion chamber 2;    -   an electronic control board 38 for controlling and/or        distributing the electrical energy between battery 9 and the        other components and/or electrical devices of the heater;    -   an electrovalve 39 for opening the fuel flow, e.g. liquid gas,        towards the supply conduit 3 when said electrovalve is        electrically activated;    -   interface devices 21 for interfacing with a user.

Such interface devices 21 may comprise e.g. buttons, knobs, selectorswitches, switches 44, warning lights, electronic displays, e.g.touch-screen, electrical connectors 35 for the removable connection ofelectric cables, inlets and/or outlets for a fluid fuel, temperaturesensors.

The heater 1 is delimited by an heater outer surface 7 comprising acavity-like portion 8 for receiving an electric battery 9 in a removablemanner up to an operative position of the battery in which battery 9 isadapted to electrically power the electrical device 4, said cavity-likeportion 8 being configured to keep battery 9 outside said outer surface7 of the heater in said operative position of the battery.

In other words, the cavity-like portion 8 may be easily accessed fromthe outside of heater 1 during the use of heater 1.

In other words, the cavity-like portion 8 is configured to receivebattery 9 so that such a battery 9 remains at least partially outsidethe heater during use.

In other words, the cavity-like portion 8 remains operatively facing theoutside of heater 1 during use.

In other words, the cavity-like portion 8 is defined by cavity walls 34,36, 37, 39 adapted to remain operatively interposed between the insideof the heater and said electric battery 9.

In other words, the cavity-like portion 8 is defined by cavity walls 34,36, 37, 39 interposed between the inside of heater 1 and the outside ofheater 1.

Thereby, the replacement of the battery is quite simple and quick andcan be executed by untrained personnel. Indeed, it is sufficient tograsp the battery in operative position and to remove it with a simplemanual movement and/or by pressing a release button, thus avoiding theneed to access the inside of the heater. This provision does not requireopening a panel for closing an inner compartment of the heater to accessthe battery. Moreover, it does not require manually disconnectingelectrical connectors arranged inside the heater.

In accordance with an embodiment, the cavity-like portion 8 comprisesconnection means for allowing the battery to electrically power theelectrical components of the heater when said battery is in theoperative position.

In accordance with an embodiment, such connection means compriseelectric contacts 22 arranged so that when the battery is in theoperative position, they come into electrical contact with correspondingelectric contacts 45 of battery 9.

Thereby, by simply manually moving the battery away from the heater, theelectrical connection is automatically disconnected.

In accordance with an embodiment, the electric contacts 22 of thecavity-like portion comprise metal laminas.

In accordance with an alternative embodiment, the connection meanscomprise electromagnetic induction means (not shown in the figures),although they are less performing than the electric contacts in terms ofenergy consumption.

In accordance with an embodiment, heater 1 does not comprise, or doesnot have, means for closing said cavity-like portion when said batteryis in the operative position. Thereby, access to the battery to bereplaced is immediate.

The cavity-like portion 8 separates the inside of heater 1 from theoutside of heater 1. Thereby, the inside of the heater is protectedagainst the involuntary introduction of foreign bodies or accidentalcontact by a user with the inner components of the heater.

The cavity-like portion 8 is joined to the heater outer surface 7 alonga cavity-like portion edge 10.

In other words, the cavity-like portion 8 faces the outside of heater 1along a cavity-like portion edge 10.

In accordance with an embodiment, the cavity-like portion 8 is joined tothe heater outer surface 7, e.g. in a fluid and/or dust tight manner.

Thereby, the battery may be replaced while avoiding a gap from beingopened for the liquids towards the inside of the heater during thereplacement of the battery, therefore capable of keeping a liquid sealalso during replacement of the battery.

In other words, the heater outer surface 7, comprising said cavity-likeportion 8, may provide a barrier to the dust and/or liquids duringoperation of the heater with the battery in the operative position,during the replacement of the battery and when the battery is removed.

Thereby, the inlet of liquids or dust inside the heater is continuouslyprevented at the cavity-like portion, both when the battery is in theoperative position and when the battery is removed. This effect isparticularly advantageous because it protects the inside of the heaterfrom liquids and dust not only during the operation of the heater whenthe battery is inserted, but also and especially during the replacementof the battery. This allows a safe replacement of the battery, also inhumid and dusty places or environments.

In accordance with an embodiment, the cavity-like portion 8 comprisesguide surfaces 11′, 11″, 11′″ adapted to allow battery 9 to slide in aguided manner between a battery inlet position and said operativeposition along a battery sliding direction B-B, said guide surfaces 11′,11″, 11′″ extending parallel to said battery sliding direction B-B.Thereby, the insertion and removal of battery 9 into/from thecavity-like portion 8 is accurate, in addition to being quick andsimple.

In accordance with an embodiment, the battery sliding direction B-B is arectilinear direction.

In accordance with an embodiment, the guide surfaces 11′, 11″, 11′″ areadapted to slidably engage with sliding engagement counter-surfaces 23,24, 25 of the battery.

In accordance with an embodiment, the guide surfaces 11′, 11″, 11′″ aresubstantially flat.

In accordance with an embodiment, the guide surfaces 11′, 11″, 11′″comprise an upper surface 11′, a lower surface 11″ opposite to the uppersurface 11′, for example substantially parallel to the upper surface11′, a lateral surface 11′″ which mutually joins the upper surface 11′with the lower surface 11″, for example substantially orthogonal to saidupper surface 11′ and/or to said lower surface 11″.

In accordance with an embodiment, the cavity-like portion 8 comprises atleast one sliding track 11 which extends parallel to said batterysliding direction B-B, the sliding track 11 being adapted to allowbattery 9 to slide in the battery sliding direction B-B.

In accordance with an embodiment, the sliding track is delimited by saidguide surfaces 11′, 11″, 11′″.

In accordance with an embodiment, the cavity-like portion 8 comprisestwo sliding tracks 11 which are substantially parallel to each other andface each other in an approaching manner to allow battery 9 to slide inthe battery sliding direction B-B.

In accordance with an embodiment, each of said tracks is defined byguide surfaces 11′, 11″, 11′″.

In accordance with an embodiment, the cavity-like portion 8 comprises astop surface 14 arranged transversely to the battery sliding directionB-B, which is adapted to stop the sliding of said battery 9 at saidoperative position.

In accordance with an embodiment, the stop surface 14 is substantiallyorthogonal to the battery sliding direction B-B.

In accordance with an embodiment, the stop surface 14 is arranged at oneinner end of said cavity-like portion 8, opposite to said cavity-likeportion edge 10.

In accordance with an embodiment, the stop surface 14 is substantiallyflat.

In accordance with an embodiment, the cavity-like portion 8 comprises alongitudinal surface 19 which is substantially parallel to said batterysliding direction B-B, which connects said stop surface 14 with saidedge 10 of the cavity-like portion.

In accordance with an embodiment, the longitudinal surface 19 issubstantially flat.

In accordance with an embodiment, the longitudinal surface 19 issubstantially orthogonal to said stop surface 14.

In accordance with an embodiment, a sliding channel 26 is formed betweenthe longitudinal surface 19 and the upper surface 11′ to slidably engagea portion of said battery 9, which extends along said battery slidingdirection B-B.

In accordance with an embodiment, the longitudinal surface 19 is facingand is substantially parallel to the upper surface 11′.

In accordance with an embodiment, a sliding channel 26 is formed betweenthe longitudinal surface 19 and said at least one sliding track 11 toslidably engage a portion of said battery 9.

In accordance with an embodiment, two respective sliding channels 26 areformed between the longitudinal surface 19 and said two sliding tracksto slidably engage two respective opposite portions of battery 27, saidtwo sliding channels 26 being parallel to and facing each other.

In accordance with an embodiment, a first channel of said two slidingchannels has a width measured in a direction which is orthogonal to thelongitudinal surface 19, which is substantially equal to the width of asecond channel of said two channels measured in direction which isorthogonal to the longitudinal surface 19.

In other words, in accordance with an embodiment, the distance betweenthe longitudinal surface 19 and the upper surface 11′ of one of said twosliding channels 26 measured in direction which is orthogonal to thelongitudinal surface 19 is substantially equal to the distance betweenthe longitudinal surface 19 and the upper surface 11′ of the two slidingchannels 26 measured in direction which is orthogonal to thelongitudinal surface 19.

In other words, in accordance with an embodiment, the distance betweenthe longitudinal surface 19 and one of the two tracks 11 issubstantially equal to the distance between the longitudinal surface 19and the other of the two tracks 11.

In accordance with an embodiment, the cavity-like portion 8 comprises afirst lateral surface 16 and a second lateral surface 17 which face eachother on opposite sides of said cavity-like portion 8, wherein suchlateral surfaces 16 and 17 connect said stop surface 14 with said edge10 of the cavity-like portion.

In accordance with an embodiment, the first lateral surface 16 and thesecond lateral surface 17 are substantially parallel to each other andparallel to the battery sliding direction B-B.

In accordance with an embodiment, the first lateral surface 16 and thesecond lateral surface 17 are substantially flat.

In accordance with an embodiment, the first lateral surface 16 and thesecond lateral surface 17 are substantially orthogonal to said stopsurface 14.

In accordance with an embodiment, the longitudinal surface 19 isinterposed between the first lateral surface 16 and the second lateralsurface 17.

In accordance with an embodiment, the first lateral surface 16 and thesecond lateral surface 17 are substantially orthogonal to thelongitudinal surface 19.

In accordance with an embodiment, the cavity-like portion 8 defines abox-like cavity structure 33 formed by cavity walls 34, 36, 37, 39.

In accordance with an embodiment, said box-like cavity structure 33 hasat least one wall which is operatively open towards the outside of theheater to allow the introduction/removal of battery 9.

In accordance with an embodiment, said cavity walls 34, 36, 37, 39comprise at least one of:

-   -   a stop wall 34 defined by said stop surface 14;    -   a longitudinal wall 39, or upper wall, defined by said        longitudinal surface 19;    -   a first lateral wall 36 defined by a first of said lateral        surfaces 16;    -   a second lateral wall 37 defined by a second of said lateral        surfaces 17.

In accordance with an embodiment, said cavity walls 34, 36, 37, 39 arejoined to one another in a fluid and/or dust tight manner.

In accordance with an embodiment, said cavity walls 34, 36, 37, 39 aremade in one piece with one another, e.g. by molding of plastics.

In accordance with an embodiment, the outer surface 7 comprises abattery gripping recessed portion 13 adjacent to said cavity-likeportion 8, and as an extension of said cavity-like portion 8, thusforming a space which can be accessed from the outside to allow anoperator to insert his finger to grasp the battery when it is in theoperative position in order to remove it.

In accordance with an embodiment, said battery gripping recessed portion13 extends from said stop surface 14 moving away from said cavity-likeportion 8.

In accordance with an embodiment, a cross-section of the batterygripping recessed portion 13 by means of a section plane which isorthogonal to an access direction in the recessed position for grippingthe battery is an open curved line, for example substantially in theshape of a semi-circumference.

In accordance with an embodiment, the area of the cross-section of thebattery gripping recessed portion 13 by means of a section plane whichis orthogonal to the stop surface 14 is decreasing proceeding from theoutside of the heater towards the inside of the heater along an accessdirection in the battery gripping recessed portion.

In other words, the battery gripping recessed portion 13 is taperedtowards the inside of the heater.

In accordance with an embodiment, the battery gripping recessed portion13 extends along a direction which is substantially orthogonal to thelongitudinal surface 19.

In accordance with an embodiment, the battery gripping recessed portion13 is defined by a battery gripping a recessed wall 18 which is roundingjoined with said stop wall 34.

In accordance with an embodiment, the heater outer surface 7 comprises afirst portion of the outer surface 7′ which is substantially transverseto said battery sliding direction B-B, in which said edge 10 of thecavity-like portion comprises a first edge portion 10′ of thecavity-like portion arranged on said first portion of the outer surface7′.

In accordance with an embodiment, the heater outer surface 7 comprises asecond portion of the outer surface 7″ adjacent to said first portion ofthe outer surface 7′ and is substantially parallel to said batterysliding direction B-B.

In accordance with an embodiment, the edge 10 of the cavity-like portioncomprises a second edge portion 10″ of the cavity-like portion whichextends on said second portion of the outer surface 7″.

In accordance with an embodiment, the second portion of the outersurface 7″ is substantially flat and the first portion of the outersurface 7′ is curved and joined with the second portion of the outersurface 7″.

In accordance with an embodiment, said battery gripping recessed portion13 penetrates into the heater from said second portion of the outersurface 7″.

In accordance with an embodiment, the cavity-like portion 8 comprises asnap engagement device 15 for retaining said battery 9 when it is insaid operative position.

In accordance with an embodiment, the snap engagement means 15 comprisea recess 47 made in said cavity-like portion 8, for movably receiving amovable coupling element 28 of said battery 9 when said battery 9 is inthe operative position.

In accordance with an embodiment, recess 47 comprises two adjacentinclined surfaces. Thereby, such surfaces facilitate the movement of themovable coupling element 28 of the battery between an engage extractedposition and a disengage compressed position.

In accordance with an embodiment, recess 47 is a blind recess. Thereby,inlet of liquids or dust into the heater through said recess 47 isprevented.

In accordance with an embodiment, recess 47 belongs to said longitudinalsurface 19, for example close to said edge 10 of the cavity-likeportion.

If there are two sliding tracks 11, said recess is interposed betweensaid two sliding tracks 11, and for example is equally spaced from saidtwo sliding tracks 11.

In accordance with an embodiment, heater 1 comprises a control box 20,said control box 20 being fixed with respect to said combustion chamber2 and defining an outer surface of the control box, said outer surfaceof the control box comprising said cavity-like portion 8.

In accordance with an embodiment, the control box 20 accommodatestherein electrical and/or mechanical components for the operation of theheater, for example such components comprise at least one of:

-   -   an electronic control board 38 for controlling and/or        distributing the electrical energy between battery 9 and the        other components and/or electrical devices of the heater;    -   an electrovalve 39 for opening a fuel flow, e.g. liquid gas,        towards the supply conduit 3 when said electrovalve is        electrically activated;    -   a manual safety valve 40 for opening or closing the fuel flow,        e.g. liquid gas, towards the supply conduit 3 when said valve is        manually activated;    -   interface devices 21 for interfacing with a user 21.

It is noted that during the operation of the heater with battery 9 inthe operative position of the battery, the battery is arranged outsidethe control box 20 while the aforesaid electrical and/or mechanicalcomponents are arranged inside the control box 20.

In accordance with an embodiment, the control box 20 comprises an inletfor fuel 41, e.g. liquid gas.

In accordance with an embodiment, the control box 20 forms a supportbase for said combustion chamber 2 and comprises said second outersurface 7″.

In accordance with an embodiment, the second portion of the outersurface 7″ is adapted to be supported on a floor or a supportingsurface.

In accordance with an embodiment, the combustion chamber 2 issubstantially tubular and extends along a main axis C-C of thecombustion chamber.

The combustion chamber has a heated air outlet opening 30 at one end ofsaid tubular combustion chamber 2.

In accordance with an embodiment, the battery sliding direction B-B issubstantially parallel to said main axis C-C of the combustion chamber.

In accordance with an embodiment, the first portion of the outer surface7′ faces the same side as said heated air outlet opening 30.

In accordance with an embodiment, the combustion chamber has acombustion air inlet 31 opposite to said heated air outlet opening 30.

In accordance with an embodiment, the electric fan 4 is arrangedupstream of the combustion chamber 2, for example facing said combustionair inlet 31.

In accordance with an embodiment, heater 1 comprises an automaticelectric switch 35 adapted to disconnect the battery power supply when apower supply from an electrical distribution network is available, andto connect the battery power supply when a power supply from anelectrical distribution network is not available.

For example, the switch 35 is socket electric connector having amechanical switch, for example mounted on the control box 20, adapted toconnect the power supply when a plug is inserted into the socketelectric connector.

In accordance with an embodiment, the heater 1 comprises a removablebattery 9 adapted to be received and retained in said cavity-likeportion 8, said removable battery 9 being delimited by an outer batterysurface 51, wherein at least one portion 42 of said outer batterysurface remains visible when said battery 9 is in said operativeposition of the battery.

Thereby, since part of the battery is always exposed to the outside, itis easily accessible without the need to open any door. This allows aquick replacement of the battery. Moreover, it may also be replacedwhile wearing a work glove. Moreover, the replacement of the batterydoes not require the use of any tool.

Battery 9 may comprise any combination of the features described above.

For example, battery 9 may comprise a button 29 which when pressed by auser, causes the movable coupling element to move from an engageextracted position to a disengage compressed position.

Although a heater having a cylindrical combustion chamber has beendescribed, the present invention may also be applied to a heater havinga conical combustion chamber, or a combustion chamber having any othershape.

The present invention may be applied to any portable fluid fuel heater,e.g. a portable liquid gas or liquid fuel heater.

If the invention is applied to a liquid fuel heater, the heater maycomprise a liquid fuel tank connected to the fuel supply conduit 3 and afuel nebulization nozzle.

The present invention may be applied e.g. to a portable air heater ofthe infrared heat radiation type.

For example, such a heater has a cone-shaped combustion chamber havingan outlet at the base of the cone and a metal grille at said outletadapted to be heated by the combustion up to such a temperature as toemit heat by radiation. This type of heater has the advantage ofgenerating a well-defined in space radiation beam and having frontrectilinear extension.

This type of infrared heater may comprise a liquid fuel tank for feedingthe combustion in the combustion chamber. Such a liquid fuel may bediesel fuel, kerosene, petrol or other liquid hydrocarbons. Furthermore,the present invention may also be applied to other types of portable airheaters.

Those skilled in the art may make several changes and adaptations to theabove-described embodiments of the device, and may replace elements withothers which are functionally equivalent in order to meet contingentneeds, without departing from the scope of the following claims. Each ofthe features described as belonging to a possible embodiment can beachieved irrespective of the other embodiments described.

1. A portable fluid fuel air heater comprising: a combustion chamber foraccommodating a combustion of a fluid fuel; a supply conduit forsupplying said fluid fuel to the combustion chamber; at least oneelectrical device required for the operation of the heater mounted onboard of the heater; an outer surface of the heater comprising acavity-like portion for receiving an electric battery in a removablemanner until reaching an operative position of the battery wherein thebattery is adapted to electrically power the electrical device, saidcavity-like portion separating the inside of the heater from the outsideof the heater and being configured to keep the battery outside theheater in said operative position of the battery.
 2. The heateraccording to claim 1, wherein said cavity-like portion comprises guidesurfaces adapted to slidably guide the battery between a battery inletposition and said operative position along a battery sliding direction,said guide surfaces extending parallel with said battery slidingdirection.
 3. The heater according to claim 2, wherein the cavity-likeportion comprises a stop surface arranged transversely to the batterysliding direction, adapted to stop the sliding of said battery at saidoperative position.
 4. The heater according to claim 1, wherein saidouter surface comprises a recessed portion for gripping the battery,adjacent to said cavity-like portion and as an extension of saidcavity-like portion, forming a space that can be accessed from theoutside to allow an operator to insert a finger to grasp the batterywhen said battery is in the operative position in order to remove it. 5.The heater according to claim 4, wherein said recessed portion forgripping the battery is developed starting from said stop surface movingaway from said cavity-like portion.
 6. The heater according to claim 1,wherein the cavity-like portion faces towards the outside of the heateralong an edge of the cavity-like portion, wherein said outer surface ofheater comprises a first portion of the outer surface substantiallytransverse to said battery sliding direction, wherein said edge of thecavity-like portion comprises a first edge portion of the cavity-likeportion arranged on said first portion of the outer surface.
 7. Theheater according to claim 6, wherein said heater outer surface comprisesa second portion of the outer surface adjacent to said first portion ofthe outer surface and substantially parallel with said battery slidingdirection, said edge of the cavity-like portion comprising a second edgeportion of the cavity-like portion which is extended on said secondouter portion surface.
 8. The heater according to claim 1, wherein saidcavity-like portion comprises a snap engagement device to retain saidbattery when it is in said operative position.
 9. Heater according toclaim 1, comprising a control box integral with said combustion chamberand defining an outer surface of the control box, said outer surface ofthe control box comprising said cavity-like portion.
 10. The heateraccording to claim 9, wherein said control box forms a support base forsaid combustion chamber and comprises said second portion of outersurface, wherein said second portion of outer portion is adapted to besupported on a floor or a supporting surface.
 11. The heater accordingto claim 2 wherein the combustion chamber is substantially tubular andis developed along a main axis of the combustion chamber and has anheated air outlet opening at an end of said tubular combustion chamber,wherein said battery sliding direction is substantially parallel withsaid main axis of the combustion chamber, and/or wherein said firstportion of the outer surface faces the same side as said heated airoutlet opening.
 12. The heater according to claim 1, comprising anautomatic electric switch adapted to disconnect the battery power supplywhen a power supply from an electrical distribution network isavailable, and to connect the battery power supply when a power supplyfrom an electrical distribution network is not available.
 13. The heateraccording to claim 1, comprising a removable battery adapted to bereceived and retained in said cavity-like portion, said removablebattery being delimited by an outer battery surface, wherein at leastone portion of said battery outer surface remains visible when saidbattery is in said operative position of the battery.